PCP pistol recomendations?

It should be very easy. You need to remove the grip assembly too. Unscrew the two screws - one in front of the trigger guard and the other at the top back of the hand grip. Don't lose the little spring on top of the sear. Then it's just the 4 hex screws to remove the valve chamber and get to the valve. 

As long as I keep pressure above 100bar I am okay, anything below that and it starts leaking through the valve.